<!DOCTYPE html>

<html>
	<head>
		<meta charset="UTF-8">
		<title>Insert title here</title>
		<style type="text/css">
			#box_div{
				width:300px;
				height:300px;
			}
			.blue{
				width:100px;
				height:100px;
				background-color: blue;
				
			}
			.red{
				width:100px;
				height:100px;
				background-color: red;
			}
		</style>
		
		<script type="text/javascript">
			function myfn(color){
				var box = document.getElementById("box_div");
			}
		</script>
	</head>
	<body>
		<input type="button" value="按钮" >
		<div id="box_div">
			
		</div>
	</body>
</html>